Thanks for that mate. I've got rid of it now.
Well my tank is a 60Litre tank and at the moment ive got 2 guppys, 2 swordtails, 3 peppered corys and a plec of about 3 inches long. Plus about 30 guppy babies. Every time ive tested the water all the levels seem to be normal.
I've been doin a 30%...